The aim of preparation of the platelet concentrate is a mixture with conserved haemostatic function. During the process of preparation and storage, the platelet structure and function is affected. It undergoes apoptosis and activation. The state of cell damage and platelets activation was evaluated by means of separators Haemonetics MCS+ and Trima Accel with different technology of apheresis. Parameters of cell damage and platelet activation (pH, LDH, lactate, glucose, annexin V, soluble P-selectin) were evaluated at a time of preparation and expiration. The lowest level of activation during the time of preparation was observed in platelets from separator Haemonetics MCS+. Higher levels of platelet activation were demonstrated by apheresis in contrast to the total blood at the time of expiration. Mixtures from both separators showed comparable results. Based on the evaluation of progression and correlation between abovementioned markers, particularly between P-selectin and annexin V, the authors suggest that initial platelet activation in the mixtures is probably reversible. It is a result of technology procedure during the preparation, which does not affect process of apoptosis and its viability during the storage.

        Key words: apheresis, platelet activation, apoptosis